CN111034235A - Beacon in a small-wavelength wireless network - Google Patents

Abstract

In an apparatus and method for communication within a mesh network, reduced signaling overhead is provided. Communication involves the use of two different beacon signals. The peer beacons contain time synchronization and resource management information to maintain existing links between one or more neighboring peer stations, while the separate network discovery beacons contain mesh network profile information identifying the mesh network to facilitate network discovery by wireless communication stations wishing to join the mesh network. Embodiments describe coordination between peer stations to determine which stations will transmit network discovery beacons such that not all stations need to transmit discovery beacons in any given time period.

Description

Beacon in a small-wavelength wireless network

Cross Reference to Related Applications

This application claims priority and benefit from U.S. provisional patent application serial No. 62/550,028, filed 2017, 8, 25, the entire contents of which are incorporated herein by reference.

Statement regarding federally sponsored research or development

Not applicable to

Incorporation of references into computer program appendix

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Copyright protected announcement of material

Some of the material in this patent document may be subject to copyright protection under the copyright laws of the united states and other countries. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. patent and trademark office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not disclaim here any rights including, but not limited to, the confidentiality of the patent document in accordance with article 1.14 of 37c.f.r.

Background

1. Field of the invention

The technology of the present disclosure relates generally to directional wireless communication between stations, and more particularly to more efficient use of beacon signaling within a multi-hop relay directional wireless communication network.

2. Discussion of background

Millimeter wavelength (mmW) wireless networks, including mesh networks and hybrids of mesh and non-mesh networks, are becoming increasingly important. As higher capacity is required, network operators have begun to accept the concept of achieving densification. The use of current wireless technology below 6GHz is not sufficient to meet high data demands. An alternative approach is to utilize additional spectrum in the 30-300GHz band millimeter wave band (mmW).

Generally, enabling mmW wireless systems requires proper handling of channel impairments and propagation characteristics of the high frequency band. High free space path loss, high penetration, reflection and diffraction losses can reduce the available diversity and limit non line of sight (NLOS) communications. The small wavelength of mmW enables the use of high gain electronically controllable directional antennas of practical size. This may provide sufficient array gain to overcome path loss and ensure a high signal-to-noise ratio (SNR) at the receiver. Directional mesh networks in densely deployed environments using mmW bands are an effective way to achieve reliable communication between nodes and overcome line-of-sight channel limitations.

The new station node that is starting up will look for neighboring nodes to discover and join the network. The initial access procedure for a node to the network involves scanning for neighboring nodes and discovering all active nodes in the local vicinity. This may be performed by the new node searching for a particular network/list of networks to join, or by the new node sending a broadcast request to join any already established networks that will accept the new node.

Nodes connected to the mesh network need to discover neighbors to decide the best way to reach the gateway/portal mesh node and the performance of each of these neighbors. The new node will check for possible neighbors in each channel for a certain period of time. If no active node is detected after the particular time, the new node will move to test the next channel. When a node is detected, the new node collects enough information to configure its PHY layer to operate in the regulatory domain (IEEE, FCC, ETSI, MKK, etc.). This task is more challenging in millimeter wave communications due to directional transmission. The challenges in this process can be summarized as: (a) knowledge of surrounding node IDs; (b) knowledge of the best transmission mode for beamforming; (c) channel access problems due to collisions and deafness; and (d) channel impairments due to blocking and reflections. Designing a neighborhood discovery approach that overcomes some or all of the above problems is critical to achieving the popularity of mmWave D2D and mesh technologies.

Most prior art of mesh networks provide mesh discovery solutions for networks operating in broadcast mode and are not directed to networks with directional wireless communication. In addition, those techniques that utilize directional wireless network communications typically have very high overhead requirements in terms of beacon signal generation.

Therefore, enhanced mechanisms for beacons within millimeter wave networks are needed. The present disclosure satisfies this need and provides many more benefits than the prior art.

Disclosure of Invention

It is important to be able to establish and maintain mmWave communications in a mesh topology network without incurring significant signaling overhead or network discovery delays. In the disclosed technique, two different types of beacon signals are utilized: (1) communication beacons (peer beacons) and (2) discovery beacons. The use of these two beacons allows the discovery function and the network maintenance function to be separated so that less information is embedded by the node Station (STA) in each of these strategic target beacons. The use of the apparatus and method of the present invention by these separate beacons reduces the signaling overhead.

The disclosed techniques coordinate discovery beacon transmissions among STAs in a network to reduce unnecessary beacon transmissions for network discovery purposes. The disclosed apparatus and method define a set of rules on how coordination should be performed in an efficient manner. For example, the disclosed techniques reduce the number of sectors used for communication (peer-to-peer) beacon transmissions to reduce the number of beacon frames to transmit. The disclosed technology also defines a set of rules that allow passive scanning and active scanning with reduced beacon overhead. Based on these rules, new stations (those attempting to join the mesh network) may discover existing networks with limited network latency.

In the present disclosure, a number of terms are used, the meanings of which are generally described below.

A-BFT: an association beamforming training period; a time period advertised in the beacon for association and BF training for new Stations (STAs) joining the network.

AP: an access point; an entity comprising a Station (STA) and providing access to distribution services for associated STAs through a Wireless Medium (WM).

Beamforming (BF): directional transmission without the use of an omni-directional antenna pattern or a quasi-omni-directional antenna pattern. Beamforming is used at a transmitter to improve received signal power or signal-to-noise ratio (SNR) at an intended receiver.

BSS: a basic service set; a group of Stations (STAs) that successfully synchronize with an AP in the network.

BI: the beacon interval is a recurring superframe period, representing the time between beacon transmission times.

BRP (bridge fragment processing): BF optimizing protocol; BF protocols, which allow for receiver training and iterative training of the transmitter and receiver sides for optimal directional communication.

BTI: a beacon transmission interval is the interval between successive beacon transmissions.

CBAP: a contention-based access period; a time period in a Data Transmission Interval (DTI) of a directional multi-gigabit (DMG) BSS, in which contention-based Enhanced Distributed Channel Access (EDCA) is used.

DTI: a data transmission interval; a full BF training period is allowed and then the actual data transmission takes place. It may include one or more Service Periods (SPs) and contention-based access periods (CBAPs).

ISS: internal sub-layer services.

MAC address: a Media Access Control (MAC) address.

MBSS: mesh basic service set, a Basic Service Set (BSS) that forms a self-contained network of Mesh Stations (MSTAs) and can be used as a Distribution System (DS).

MCS: a modulation and coding scheme; an index is defined that can be translated to the PHY layer data rate.

MSTA: mesh Station (MSTA): a Station (STA) implementing a mesh facility. An MSTA operating in a mesh BSS may provide distribution services to other MSTAs.

Omnidirectional orientation: an omni-directional antenna transmission mode.

Quasi-omnidirectional orientation: a directional multi-gigabit (DMG) antenna mode of operation with maximum beamwidth.

Receive sector sweep (RXSS): sector Sweep (SSW) frames are received over different sectors, with the sweep being performed between successive receptions.

RSSI: received signal strength indicator (in dBm).

SLS: sector level scanning phase: the BF training phase, may include up to four parts: initiator Sector Sweep (ISS) training the initiator, and Responder Sector Sweep (RSS) training linked to using SSW feedback and SSW ACK.

SNR: the received signal-to-noise ratio, in dB.

SP: a service period; access Point (AP) planned SPs. The planned SP starts at a fixed time interval.

Spectral efficiency: the rate of information that can be transmitted over a given bandwidth in a particular communication system is typically in bits/second or hertz.

SSID: a service set identifier; name assigned to WLAN network.

STA: a station; a logical entity, which is a single addressable instance of a Media Access Control (MAC) and physical layer (PHY) that interfaces with the Wireless Medium (WM).

Scanning: a series of transmissions separated by short beam shaping interframe space (SBIFS) intervals, wherein the antenna configuration of a transmitter or receiver changes between transmissions.

SSW: sector scanning, is an operation in which transmissions are performed in different sectors (directions) and information on received signals, strength, etc. is collected.

Transmit sector sweep (TXSS): scanning is performed between successive transmissions by transmitting multiple Sector Sweep (SSW) or directional multi-gigabit (DMG) beacon frames in different sectors.

Additional aspects of the technology described herein will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the technology.

Drawings

The techniques described herein will be more fully understood with reference to the following drawings, which are for illustrative purposes only:

fig. 1 is a timing diagram of an active scan performed in an IEEE802.11 Wireless Local Area Network (WLAN).

Fig. 2 is a node diagram for a mesh network showing a combination of mesh and non-mesh stations.

Fig. 3 is a data field diagram depicting a mesh identification element for an IEEE802.11 WLAN.

Fig. 4 is a data field diagram depicting a mesh configuration element for an IEEE802.11 WLAN.

Fig. 5 is a schematic diagram of antenna Sector Sweep (SSW) in the IEEE802.11ad protocol.

Fig. 6 is a signaling diagram illustrating signaling for Sector Level Scanning (SLS) in the IEEE802.11ad protocol.

Fig. 7 is a data field diagram depicting a Sector Sweep (SSW) frame element for IEEE802.11 ad.

Fig. 8 is a data field diagram depicting SSW fields within an SSW frame element for IEEE802.11 ad.

Fig. 9A and 9B are data field diagrams depicting SSW feedback fields that are transmitted as part of the ISS in fig. 9A when used as ieee802.11ad and are shown when not transmitted as part of the ISS in fig. 9B.

Fig. 10 is a wireless node topology of an example wireless mmWave node in a wireless network used in accordance with an embodiment of the disclosure.

Fig. 11 is a block diagram of station hardware used in accordance with an embodiment of the present disclosure.

Fig. 12 is a beam pattern of the station hardware of fig. 11 used in accordance with an embodiment of the present disclosure.

Fig. 13A-13C are wireless node topologies and associated discovery beacon scans according to embodiments of the present disclosure.

Fig. 14 is a communication cycle diagram illustrating transmission and reception from a mesh node according to an embodiment of the present disclosure.

Fig. 15A to 15D are wireless node topologies on which a beacon master method is described according to an embodiment of the present disclosure.

Fig. 16 is an antenna pattern of a coverage area showing a result of coordination between nodes according to an embodiment of the present disclosure.

Fig. 17 is a sector scan diagram for a mesh network discovery frame according to an embodiment of the present disclosure.

Fig. 18A and 18B are wireless node topologies on which to perform bounding of optimal sector communication directions according to embodiments of the disclosure.

Fig. 19 is a flow chart of transmitting peer beacons according to an embodiment of the disclosure.

FIG. 20 is a flow diagram of training database creation and update according to an embodiment of the present disclosure.

Fig. 21 is a communication cycle diagram illustrating a beacon master transmitting discovery beacons in all directions according to an embodiment of the present disclosure.

Fig. 22 is a communication cycle diagram illustrating a peer-to-peer beacon superframe format according to an embodiment of the present disclosure.

Fig. 23A-23C are wireless node diagrams of primary beacon forwarding and advertising performed in accordance with an embodiment of the present disclosure.

Fig. 24A-24C are wireless node diagrams of different nodes assuming a beacon master role according to embodiments of the disclosure.

Fig. 25A to 25E are wireless node diagrams of a main beacon interrupt process according to an embodiment of the present disclosure.

Fig. 26A and 26B are flow diagrams of random primary beacon selection according to embodiments of the present disclosure.

Fig. 27A and 27B are flow diagrams of sequence-based primary beacon selection according to embodiments of the present disclosure.

Fig. 28 is an antenna pattern illustrating a coverage area responsive to a cooperative coverage area between nodes according to an embodiment of the present disclosure.

Fig. 29A-29C are node sector coverage maps used in accordance with embodiments of the present disclosure.

Fig. 30 is a messaging diagram for a new node performing a passive scan to admit to a mesh network according to an embodiment of the present disclosure.

Fig. 31 is a messaging diagram for a new node performing an active scan to admit to a mesh network according to an embodiment of the present disclosure.

Fig. 32 is a node sector coverage map illustrating sector coverage between nodes utilized in accordance with an embodiment of the present disclosure.

Fig. 33 is a node sector coverage map showing sector coverage between nodes where new nodes have an effect on moving through coverage areas, according to an embodiment of the disclosure.

Fig. 34A and 34B are flow diagrams of discovering and joining a new node of a mesh network according to an embodiment of the disclosure.

Fig. 35 is a flow diagram of a new node admitted beacon master process according to an embodiment of the disclosure.

Fig. 36A and 36B are messaging diagrams performed in accordance with an embodiment of the present disclosure to allow a new node to enter a mesh network, coordinated by a central controller entity that is out of range of the new node.

Fig. 37 is a messaging diagram for allowing a new node to enter a mesh network, coordinated by a central controller entity within range of the new node, performed in accordance with an embodiment of the present disclosure.

Fig. 38A and 38B are communication cycle diagrams in performing a secondary discovery process according to an embodiment of the present disclosure.

Detailed Description

1. Existing directed wireless network technology

1.1, WLAN System

In WLAN systems, 802.11 defines two scanning modes: passive and active scanning. The following is a feature of the passive scanning. (a) A new Station (STA) attempting to join the network checks each channel and waits for a beacon frame until MaxChannelTime. (b) If no beacon is received, the new STA moves to another channel, thus saving battery power because the new STA does not transmit any signals in the scanning mode. The STA should wait enough time on each channel so that it does not lose beacons. If the beacon is lost, the STA should wait for another Beacon Transmission Interval (BTI).

The following is a feature of active scanning. (a) A new STA that wants to join the local network transmits a probe request frame on each channel according to the following. (a) (1) the STA moves to the channel waiting for an incoming frame or the sounding delay timer to expire. (a) And (2) if no frame is detected after the timer expires, the channel is considered unused. (a) (3) if the channel is not used, the STA moves to a new channel. (a) (4) if the channel is being used, the STA obtains access to the medium using a conventional DCF and transmits a probe request frame. (a) (5) if the channel is never busy, the STA waits a desired period of time (e.g., a minimum channel time) to receive a response to the probe request. If the channel is busy and a probe response is received, the STA waits more time (e.g., maximum channel time).

(b) The probe request may use a unique Service Set Identifier (SSID), a list of SSIDs, or a broadcast SSID. (c) Active scanning is prohibited in certain frequency bands. (d) Active scanning may be a source of interference and collisions, especially if many new STAs arrive at the same time and attempt to access the network. (e) Active scanning is a faster (faster) way for STAs to gain access to the network than using passive scanning, since the STAs do not need to wait for beacons. (f) In an infrastructure Basic Service Set (BSS) and an IBSS, at least one STA is in an awake state to receive and respond to a probe. (g) STAs in the Mesh Basic Service Set (MBSS) may not be able to wake up to respond at any point in time. (h) When radio measurement activities are conducted, the node may not be able to answer the probe request. (i) Collisions of probe responses may occur. The STAs may coordinate the transmission of the probe responses by allowing the STA that transmitted the last beacon to transmit the first probe response. Other nodes may follow and use back-off times and conventional Distributed Coordination Function (DCF) channel access to avoid collisions.

Fig. 1 depicts the use of active scanning in an IEEE802.11 WLAN, depicting a scanning station transmitting a probe and two responding stations receiving and responding to the probe. The figure also shows the minimum and maximum probe response times. A value G1 is shown set to SIFS, which is the inter-frame space before sending an acknowledgement, and G3 is DIFS, which is the DCF inter-frame space, representing the time delay for the sender to wait after completing the backoff period before sending the RTS packet.

1.2 IEEE802.11 s mesh WLAN

IEEE802.11 s (hereinafter 802.11s) is a standard that adds wireless mesh network functionality to the 802.11 standard. 802.11s defines new radio stations and new signaling to enable mesh discovery, establish peer-to-peer connections, and route data through the mesh.

Fig. 2 shows an example of a mesh network where a mix of non-mesh STAs connect to a mesh STA/AP (solid line) and a mesh STA connects to other mesh STAs including a mesh portal (dashed line). Nodes in the mesh network discover neighbors using the same scanning techniques defined in the 802.11 standard. The identification of the mesh network is given by the mesh ID element contained in the beacon and probe response frames. In a mesh network, all mesh STAs use the same mesh profile. If all the parameters in the mesh profile match, the mesh profile is considered identical. The mesh profile is contained in "beacon" and "probe response" frames so that its neighbors can obtain the mesh profile by scanning.

When a mesh STA discovers a neighbor mesh STA through a scanning process, the discovered mesh STA is considered a candidate peer mesh STA. It may become a member of the mesh network of which the discovered mesh STA is a member and establish a mesh peer-to-peer with the neighbor mesh STA. When a mesh STA uses the same mesh profile as indicated by the received beacon or probe response frame for a discovered neighbor mesh STA, the neighbor mesh STA may be considered a candidate peer mesh STA.

The mesh STA attempts to maintain information of the discovered neighbors in a mesh neighbor table, including: (a) a neighbor MAC address; (b) a working channel number; (c) recently observed link status and quality information. If no neighbors are detected, the mesh STA uses the mesh ID as its highest priority profile and remains active. All previous signaling for discovering neighbor mesh STAs is performed in broadcast mode. It should be understood that 802.11s is not directed to networks with directional wireless communication.

Fig. 3 shows a mesh identification element (mesh ID element) for advertising the identification of a mesh network. Mesh IDs are transmitted in probe requests by new STAs willing to join the mesh network and in beacons and signals by existing mesh network STAs. The mesh ID field of length 0 represents a wildcard mesh ID, which is used within the probe request frame. The wildcard mesh ID is a specific ID that prevents non-mesh STAs from joining the mesh network. It should be appreciated that a mesh station is a STA that has more features than a non-mesh station, e.g., as if the STA were operating as a module in addition to some other modules to serve mesh functions. If a STA does not have this mesh module, it should not be allowed to connect to the mesh network.

Fig. 4 depicts a mesh configuration element that is included in beacon frames and probe response frames transmitted by mesh STAs and used to advertise mesh services. The main contents of the mesh configuration elements are: (a) a routing protocol identifier; (b) a path selection metric identifier; (c) a congestion control mode identifier; (d) a synchronization method identifier; (e) the protocol identifier is authenticated. The contents of the mesh configuration element, along with the mesh ID, form a mesh configuration file.

Standard 802.11a defines a number of procedures and mesh functions, including: mesh discovery, mesh peer-to-peer management, mesh security, mesh beaconing and synchronization, mesh coordination function, mesh power management, mesh channel switching, three address, four address and extended address frame format, mesh routing and forwarding, interworking with external networks, mesh internal congestion control and emergency services support in mesh BSS.

1.3 millimeter waves in WLAN

A WLAN in the millimeter-wave band typically requires the use of directional antennas for transmission, reception, or both to account for high path loss and to provide adequate SNR for communications. The use of directional antennas in transmission or reception also makes the scanning process directional. Ieee802.11ad and the new standard 802.11ay define procedures for scanning and beamforming for directional transmission and reception over the millimeter-wave band.

1.4, IEEE802.11ad Scan and BF training

One example of the most advanced system of millimeter wave WLANs is the 802.11ad standard.

1.4.1, Scan

The new STA operates in either passive or active scanning mode to scan for a particular SSID, SSID list or all discovered SSIDs. For passive scanning, the STA scans for DMG beacon frames containing the SSID. For active scanning: the DMG STA sends a probe request frame containing the required SSID or one or more SSID list elements. The DMG STA may also have to transmit a DMG beacon frame or perform beamforming training before transmitting the probe request frame.

1.4.2 BF training

BF training is a bi-directional sequence of BF training frame transmissions that uses sector scanning and provides the necessary signaling to allow each STA to determine the appropriate antenna system settings for both transmission and reception.

The 802.11ad BF training process may be performed in three phases. (1) A sector level scan phase is performed to perform directional transmission of low gain (quasi-omni) reception for link acquisition. (2) A refinement phase is performed, increasing the receive gain and the final adjustment to the combined transmission and reception. (3) Tracking is then performed during the data transmission to adjust for channel changes.

1.4.3, 802.11ad SLS BF training phase

The Sector Level Sweep (SLS) enforcement phase of the 802.11ad standard is emphasized. During SLS, a pair of STAs exchange a series of Sector Sweep (SSW) frames (or beacons in the case of PCP/AP transmission sector training) over different antenna sectors to find the frame that provides the highest signal quality. The station transmitting first is called the initiator and the second is called the responder.

During transmit sector sweep (TXSS), SSW frames are transmitted on different sectors, while the partner (responder) receives with a quasi-omni pattern. The responder determines the antenna array sector from the initiator that provides the best link quality (e.g., SNR).

FIG. 5 depicts the concept of Sector Sweep (SSW) in 802.11 ad. In this figure, an example is given in which STA 1 is the initiator of the SLS and STA 2 is the responder. STA 1 scans the fine sector of all transmit antenna patterns while STA 2 receives in quasi-omni mode. STA 2 feeds back the best sector received from STA 1 to STA 2.

Fig. 6 illustrates the signaling of the Sector Level Sweep (SLS) protocol implemented in the 802.11ad specification. Each frame in the transmit sector sweep includes information about a sector reciprocal indicator (CDOWN), a sector ID, and an antenna ID. The best sector ID and antenna ID information is fed back along with the sector sweep feedback and sector sweep ACK frames.

Fig. 7 depicts the fields of a sector sweep frame (SSW frame) used in the 802.11ad standard, which are summarized below. The duration field is set to the time until the end of the SSW frame transmission. The RA field contains the MAC address of the STA as the intended recipient of the sector sweep. The TA field contains the MAC address of the transmitter STA of the sector sweep frame.

FIG. 8 shows data elements within the SSW field. The main information passed in the SSW field is as follows. The direction field is set to 0 indicating that the beamforming initiator transmitted the frame and set to 1 indicating that the beamforming responder transmitted the frame. The CDOWN field is a countdown counter that indicates the number of remaining DMG beacon frame transmissions to the end of the TXSS. The sector ID field is set to indicate a sector number through which a frame including the SSW field is transmitted. The DMG antenna ID field indicates the DMG antenna that the transmitter is currently using for the transmission. The RXSS length field is valid only when transmitting in CBAP, otherwise it is reserved. The RXSS length field specifies the length of the receive sector sweep required by the transmitting STA and is defined in units of SSW frames. The SSW feedback field is defined as follows.

Fig. 9A and 9B depict SSW feedback fields. The format shown in fig. 9A is used when transmitting as part of an Internal Sublayer Service (ISS), and the format of fig. 9B is used when not transmitting as part of an ISS. The total sectors number field in the ISS indicates the total number of sectors used by the initiator in the ISS. The RX DMG antenna number subfield indicates the number of receive DMG antennas used by the initiator during a subsequent Receive Sector Scan (RSS). The sector select field contains the value of the sector ID subfield of the SSW field in the frame that was received with the best quality in the previous sector sweep. The DMG antenna selection field indicates the value of the DMG antenna ID subfield of the intra SSW field received with the best quality in the immediately preceding sector sweep. The SNR report field is set to the SNR value from the frame received with the best quality during the previous sector sweep, which is indicated in the sector select field. The non-PCP/non-AP STA will need to poll field set to 1 to indicate that it requires the PCP/AP to initiate communication with the non-PCP/non-AP. The poll required field is set to 0 to indicate that the non-PCP/non-AP has no preference for the PCP/AP to initiate communication.

2. Question statement

As discussed in the previous section, current millimeter wave (mmWave) communication systems typically require heavy reliance on directional communication to obtain a sufficient link budget between the transmitter and receiver. In current systems, this process of determining the appropriate beam for use requires a significant amount of signaling overhead. For example, the AP transmits a plurality of beacon frames with transmit beamforming.

The beacon frame is used for network discovery purposes, i.e. passive scanning. For this, a beacon frame is periodically transmitted so that a new STA can recognize the presence of a network by performing passive scanning for a certain period of time.

To further complicate matters, current techniques are moving towards using finer beamforming, which allows for higher antenna gain to ensure better link budget. However, when the STA employs finer beams, the overhead problem is further exacerbated because the STA will transmit a greater number of beacon frames to cover a sufficient transmission angle.

In view of the above, there is an important tradeoff between beacon overhead and network discovery delay. If beacons are transmitted frequently, beacon overhead increases, but allows new STAs to quickly find an existing network. Beacon overhead can be reduced if the transmission frequency of beacons is low, but it is difficult for a new STA to quickly find an existing network.

This overhead dilemma is exacerbated when considering the task of forming a mesh network using mmWave PHY technology. STAs connected to the mesh network need to discover all neighboring STAs to decide the best way to reach the gateway/portal mesh STA and the capabilities of each of these neighboring STAs. This means that all STAs joining the mesh network should have beacon capability, which results in a large amount of signaling overhead.

Accordingly, the present disclosure is configured to address these current and future beacon overhead challenges.

3. Benefits of the disclosed efficient beacons

By utilizing the proposed techniques, mmWave communication nodes may form a mesh topology network without incurring significant signaling overhead or network discovery delays. The disclosed technique decomposes beacons into two different types of beacon signals: (1) communication beacons (peer beacons) and (2) discovery beacons. Creating these separate beacons can separate the discovery and network maintenance functions so that the STA can only embed the necessary information into the functionality of each beacon. Using this separation of beacons in the manner described reduces signaling overhead.

The disclosed efficient beacon techniques use coordination of discovery beacon transmissions among STAs in a network to reduce unnecessary beacon transmissions for the purposes of network discovery. The technique defines a set of rules on how the communication transceiver performs this coordination in an efficient manner. The proposed technique reduces the number of sectors used for communication (peer-to-peer) beacon transmission, which allows for a reduction in the transmission of beacon frames. The technique defines a set of rules that allow passive scanning and active scanning while reducing beacon overhead. Based on these rules, the new STA can discover existing networks with limited network delay.

4. Efficient beacon embodiments

4.1 topology under consideration

Fig. 10 illustrates an example embodiment 10 of a network of mmW wireless nodes, where mesh sta (msta) nodes 12, 14, 16, and 18 are connected to each other in a mesh topology. The new STA 20 is scanning 24, depicting directions 22a-22n, potential neighboring MSTAs and the communication medium to the node.

It should be noted that neither party always needs to transmit or receive directionally. For example, one side may be performing directional transmission or reception while the other side is not. This may be due to application requirements where the device functionality is limited or directional transmission from both sides is not required (interference limited/small distance).

A quasi-omni directional or directional antenna may be configured for the new node to transmit and receive. The MSTA may be similarly set to transmit and receive using an omni-directional or quasi-omni or directional antenna. At least one node MSTA or the new STA should configure the directional antenna to provide sufficient gain to account for path loss and provide sufficient SNR for the link.

The new STA scans for neighbors using passive or active scanning. The new STA is configured to continue scanning until all neighboring nodes are found. Having constructed the available MSTA neighbor list, it is decided which neighbor to connect with. This decision takes into account the application requirements, traffic load in the network and radio channel conditions.

4.2 STA hardware configuration

Fig. 11 depicts an example embodiment 30 of a node hardware configuration. In this example, a Computer Processor (CPU)36 and memory (RAM)38 are coupled to a bus 34, the bus 34 being coupled to an I/O path 32 that provides node-external I/O, such as sensors, actuators, and the like. Instructions from the memory are executed on the processor to execute a program implementing a communication protocol. The host is shown configured with a modem 40, the modem 40 being coupled to Radio Frequency (RF) circuitry 42a, 42b, 42c and to a plurality of antennas 44a-44n, 46a, 46n, 48a-48n to transmit and receive frames with neighboring nodes.

Although three RF circuits are shown in this example, embodiments of the present disclosure may be configured with a modem 40 coupled to any number of RF circuits. Typically, the use of a large number of RF circuits will result in a wider coverage of the antenna beam direction. It should be understood that the number of RF circuits and the number of antennas utilized is determined by the hardware constraints of the particular device. Certain RF circuitry and antennas may be disabled when a STA determines that communication with a neighboring STA is not required. In at least one embodiment, the RF circuitry includes a frequency converter, array antenna controller, etc., and is connected to a plurality of antennas that are controlled to perform beamforming for transmission and reception. In this manner, the STA may transmit signals using multiple sets of beam patterns, each beam pattern direction being considered an antenna sector.

The antenna sectors are determined by the selection of radio frequency circuitry and are beam-formed controlled by an array antenna controller. Although the STA hardware components may have different functional partitions than the components described above, such a configuration may be considered a variation of the illustrated configuration. Certain RF circuitry and antennas may be disabled when a node determines that communication with a neighboring node is not required.

In at least one embodiment, the RF circuitry includes a frequency converter, array antenna controller, etc., and is connected to a plurality of antennas that are controlled to perform beamforming for transmission and reception. In this way, the node may transmit signals using multiple sets of beam patterns, each beam pattern direction being considered an antenna sector.

Fig. 12 shows an example embodiment 50 of antenna directions that may be used by a node to generate multiple (e.g., 36) antenna sector patterns. In this example, the node implements three RF circuits 52a, 52b, 52c and connected antennas, and each RF circuit and connected antenna generates 12 beamforming patterns 56a, 56b, 56c through 56n and beamforming patterns 58 and 60; the node is said to have 36 antenna sectors. However, for clarity and ease of explanation, the following sections describe nodes with a smaller number of antenna sectors. It should be understood that any arbitrary beam pattern may be mapped to an antenna sector. Generally, the beam pattern is formed to produce a sharp beam, but the beam pattern may be produced to transmit or receive signals from multiple angles.

4.3 mesh network architecture

4.3.1 Beacon function

The functions of beacons in the mmwave mesh network may include: (a) network discovery and association of new mesh nodes; (b) synchronizing; (c) spectrum access and resource management. In the embodiments described herein, any signal used for the above functions is referred to as a beacon, and thus any signal used for those purposes should be interpreted as a beacon signal. In the next section, the 802.11 beacon is used as an example to cover this function, but other frames may be used to achieve the same function.

4.3.2, Beacon type

Based on the different functions of beacons in the network, two types of beacons are proposed in the following embodiments, namely communication beacons (or peer-to-peer beacons) and discovery beacons.

Communication or peer-to-peer beacons are used for communication between peers having a (previously) established connection. The beacon may be used to perform functions related to maintaining synchronization, beam tracking, and managing channel access and resources between mesh nodes in the network. Each mesh node scans for beacons only in sectors corresponding to the direction of neighboring nodes, and therefore only transmits beacons to its neighbors.

Discovery beacons are used for network advertisements and node discovery. Discovery beacons are used to help new nodes find and join the mesh network. Existing mesh nodes will scan for discovery beacons in all directions intended to be covered spatially. Discovery beacons may generally be sent less frequently than peer beacons to avoid uncoordinated beacon transmissions from different nodes belonging to different mesh networks and to limit interference.

Fig. 13A-13C illustrate aspects of a simple network considered by way of example and not limitation. In FIG. 13A, the exemplary embodiment 70 is seen to have three nodes 72, 74, and 76. In fig. 13B, beacons are shown transmitted from the STA node 72, showing peer-to-peer beacons being scanned 76a, 76B in a direction corresponding to the best sector toward the nodes 74 and 76. In fig. 13C, STA node 72 scans 80 for discovery beacons to cover specific spatial regions from 78a, 78b, 78C, 78d, and 78 e.

Fig. 14 illustrates an example embodiment 90 of different transmit and receive periods 98 of a mesh node across a time span 100. In this example, according to the present disclosure, the node operates in at least three periods. (1) The beacon interval 96 is the regular beacon transmission interval defined in 802.11. A communication or peer-to-peer beacon is sent to the node neighbor peers at each beacon interval. (2) The discovery period 94 is the period of time (number of beacon intervals) for which the node transmits a discovery beacon in addition to a peer beacon. Outside the discovery period, only peer beacons are transmitted. The beacon master interval 92 is the period of time for the node to repeat its discovery cycle and resend discovery beacons. If the discovery period is equal to the beacon master interval, the node is transmitting beacons all the time and acts as a regular 802.11 node. In the above and other embodiments described herein, it should be appreciated that the discovery beacon need not take the form of a conventional beacon. The discovery beacon may be any frame that sweeps through some or all of the beam directions to advertise the mesh network and discover new nodes. In this case, the period or isolation operation to transmit the frames may be defined independently of the peer beacon period.

4.3.3 Beacon Master and Beacon Master functionality

A Beacon Master (BM) is a node that selects for transmission of discovery beacons for a certain period of time. At any point in time, a beacon master is the node that sends the discovery beacon. Many nodes may be selected and scheduled to transmit discovery beacons simultaneously, but the situation described herein is to allow one beacon master at a time through the network to eliminate interference.

The functionality of the beacon master may compromise (compromise) the following: (a) scanning for a discovery beacon; (b) receiving and processing a new BM request; (c) scheduling a new BM schedule according to the received BM request; (d) updating a steady state BM sequence; (e) defining a scanning receiving direction of a new node joining the mesh network; (f) the discovery beacon scanning direction is updated for peers joining a new node of the mesh network.

4.3.4, System architecture

4.3.4.1 Beacon Master sequence

Each active node in the mesh network will become a Beacon Master (BM) according to the selected order. The sequence remains in effect until an existing mesh node can discover a new node. The BM sequence is modified to enable efficient discovery of new nodes. If a new node joins the network, the steady state BM sequence will include a diversion for the new node to act as a BM.

Fig. 15A to 15D illustrate a beacon master concept. In fig. 15A, the mesh nodes a 112, B114, C116, D118 are shown with a new node E120. In fig. 15B, it is seen that node C receives a message from node B conveying that it has received (indicated by the top arrow) a request from node E to join the network. As shown by shading in fig. 15C, the next Beacon Master (BM) may be temporarily selected as node B and node a. Then, if node E joins the network, the steady state sequence of BMs will include it.

4.3.4.2 mesh node directional passive scan pattern of new node

Consider the case where the mesh nodes are in an idle receive state, e.g., they are neither transmitting nor scheduled to receive data from peer nodes. This embodiment proposes a cooperative passive scanning mode for mesh nodes, where the nodes listen directionally to detect requests from new nodes willing to join the network.

Fig. 16 depicts the direction 130 heard by the node, as indicated by the dashed cone. In particular, it can be seen that node 132a is listening in area 134a, node 132b is listening in area 134b, node 132c is listening in area 134c, node 132d is listening in area 134d, and node 132e is listening in area 134e, as many nodes as there are in the local mesh. It can be seen that these listening areas are arranged to provide sufficient reception coverage over the area 136 so that requests can be correctly received from any new node within the area.

These directions may be coordinated by a central entity or locally, and each node may listen to all or a subset of its receiver antenna pattern sectors. The direction may be updated dynamically based on current network scheduling or in a semi-statically assigned manner based on average link usage. In the figure, the cooperation of several mesh nodes to cover the reception of signals of a given reception area can be identified.

4.3.4.3 New node active Scan mode

In at least one embodiment, a node willing to join a mesh network may perform an active scan of surrounding mesh nodes. The active scanning may be performed by scanning probe requests between different sectors supported by the node's antenna pattern.

Fig. 17 illustrates an embodiment 150 of a node 152, the node 152 transmitting in directions 154a through 154n during a scan 156 of a mesh network discovery frame in a quasi-omni transmission.

4.4 efficient BF training by peer-to-peer and discovery beacons

4.4.1, Peer-to-Peer Beacon update

In directional communications, for example, in at least one embodiment of the present disclosure, 60GHz WLAN beacon transmissions may be used as part of BF training required to establish reliable communications between peers. The discovery beacon described herein may initiate BF training, e.g., using the SLS phase.

The mesh node records the best sector information in BF training that occurs during and shortly after the transmission of the discovery beacon. For peer-to-peer beacons, the mesh node transmits a beacon to the peer-to-peer mesh node only in the sector corresponding to the best sector.

Fig. 18A and 18B illustrate example embodiments that provide additional robustness by performing transmissions on one or more sectors surrounding (encompassing) the determined best sector. In fig. 18A, node a172 is seen relative to node B174, where the best sector (path) is direction 176. In fig. 18B, node a, which is in communication with node B, has an optimal sector 178B, but one or more additional sectors 178a, 178c are also selected on each side of this optimal sector to improve communication robustness, especially in view of the fact that node B may move relative to node a.

Fig. 19 shows an example embodiment 190 of peer beacon transmission by a mesh node. The routine starts 192 and if the Beacon Interval (BI) timer has expired, a check is performed 194. If not, the timer is decremented 196 before another check is performed. It should be noted that the use of timing "loops" is shown for purposes of illustration, however, providing delays (synchronization) may be performed by any desired operating system primitive, such as synchronization and timing mechanisms utilized in a threaded or multi-tasking environment.

After the BI timer expires, block 198 initializes a node count n and then retrieves best sector information s (n)200 from the record 208 of best sectors to node n. At 202 pairs of sectors S (n)+Node n on q performs a communication beacon scan. A check 204 is then made whether any nodes still need to be checked (N < N). If there are nodes remaining, the node value is updated 206 (e.g., n +1 in this example) to the next node and the process returns to step 200 to retrieve the best sector information. Once all nodes have been examined, a data exchange is performed 210 with the peer mesh nodes and the process ends 212.

Fig. 20 illustrates an embodiment 230 of training database creation and update. After several Beacon Intervals (BI), the BF training may need to be updated. The discovery beacon provides a refresh period for BF training or BF training with new peer nodes.

The process begins at 232 by receiving a discovery beacon 234 from STA n and then retrieving 236 the STA n entry in the best sector record from the best sector record 238. A check 240 is made to determine if STA n has an entry in the best sector record. If there is no such entry, an entry 242 is added to the best sector record 238. Otherwise, if there is an existing entry, the existing data and current data are compared 244 and the BF training information is updated 246 for STA n before processing ends 248.

4.5 Steady-State BM handling protocol

4.5.1 Primary Beacon Handover

Network in steady state in accordance with at least one embodiment of the present invention, the beacon masters are moved (rotated) between network nodes, for example, in a particular order.

Fig. 21 illustrates an example embodiment 250 of a transmission 252 showing beacon masters transmitting discovery beacons in all directions 254 and peer beacon directions 260a and 260 b. In addition, the transmission of an associated beamforming training period (A-BFT)256 and a Data Transmission Interval (DTI)258 is shown.

Fig. 22 illustrates an example embodiment 270 of a peer-to-peer beacon superframe format, showing a set of transmissions 272. Nodes with peer-to-peer connectivity continue to transmit peer-to-peer beacons to each other. In this example, peer beacon is sent 274a to peer 1 and peer beacon is sent 274b to peer 2. An a-BFT transmission 274c is sent for peer 1 and an a-BFT transmission 274d is sent for peer 2. DTI transmission 276 is shown sent after the a-BFT transmission. It should be appreciated that peer-to-peer beacons are easily coordinated since the direction and timing of each peer-to-peer link is known.

The system is configured in at least one embodiment such that the order in which peer beacons are exchanged provides that all nodes act as beacon masters at a time. However, it should be understood that embodiments are also contemplated in which beacon master selection is further controlled based on selection criteria, or in which incentives (e.g., network message priority) are applied to participants that are beacon masters.

The peer-to-peer beacons and discovery beacons carry information about the current beacon master node. Both the peer beacons and the discovery beacons carry information about future beacon masters. This information may be the ID of the next node to be the beacon master or a sequence ID that determines the upcoming beacon master assignment. The peer-to-peer beacon carries information about the transmission schedule and other elements required for synchronization and data transmission of the peer-to-peer connection. Discovery beacons are simpler and preferably (e.g., in one or more embodiments) used only for network advertisement and discovery purposes. The a-BFT period of the peer beacon will carry a number of a-BFT slots equal to the number of active peer links as shown in fig. 22. The a-BFT period of the discovery beacon carries a number of a-BFT time slots that the peer node and the new node will randomly access.

4.5.2 Peer-to-Peer beacons for managing Primary Beacon exchanges

Fig. 23A-23C depict nodes interacting in the process of forwarding a primary beacon advertisement over a network by peer-to-peer beacons. The nodes seen in the figure include: MSTA a 292, MSTA B294, MSTA C296, MSTA D298, MSTAE 300. In each figure, MSTA a 292 is considered a beacon master that will send discovery beacons 302 in all directions of scan 304.

Once the mesh node takes over the master beacon rule, it starts sending discovery beacons and peer-to-peer beacons with its ID as the current beacon master and information about the next beacon master, the sequence ID, or the next beacon master. The peer beacon will be received by the nodes connected to the primary beacon to indicate that the primary beacon is active and begin its rules. The peer of the master beacon starts transmitting peer-to-peer beacons to other mesh nodes in the network to advertise the new master beacon in the network. In fig. 23A, peer beacons 306a, 306B advertise to MSTA B294 and MSTA B296, respectively, that the new beacon master is now active and that the timer is set. Each node that receives a peer beacon with a new master beacon advertisement forwards it to its peers. In fig. 23A, the old MB announcement is transmitted from MSTA B294 to MSTA E300. After a certain number of hops, the cluster should be informed of the information that the new beacon master follows its rules. The mesh node will continue to send the old primary beacon ID and a timer equal to zero before it receives a new primary beacon activation announcement either through one of its peers or the primary beacon itself. This indicates that the network is in a transitional state. Fig. 23B shows that the new MB announcement is passed 310 from MSTA B294 to MSTA E300, while it is seen that the old MB announcement 312 passes between MSTA E300 and MSTA D298. In fig. 23C, it is seen that a new MB announcement is passed 314 from MSTA B294 to MSTA E300, the time BM time value is reduced by a factor of two.

4.5.3 New Primary Beacon selection criteria

In this embodiment, the nodes of the network alternate, fulfilling the role of beacon master for each master beacon interval. At each master beacon interval, one node will act as a beacon master and transmit discovery beacons in all directions.

Fig. 24A-24C illustrate example embodiments 330 of different nodes acting as primary beacons. In the figure, the nodes can be seen to include MSTA a 332, MSTA B334, MSTA C336, MSTA D338, MSTA E340. In fig. 24A, MSTAA 332 is a beacon master that sends discovery beacon 342 in scan 344 in all directions. It is seen that the other nodes B, C, D and E only transmit peer beacons between peer nodes. In fig. 24B, MSTA C336 has become the beacon master and is sending discovery beacons 342 in scans 344 in all directions, and similarly in fig. 24C MSTA B334 assumes the beacon master role. The master beacon advertises information about current and future beacon masters and transmission timings through peer-to-peer beacons and discovery beacons. The order in which the primary beacons change may be determined in any desired manner, such as randomly or according to a particular sequence, according to availability or other criteria for each given node. However, it should be considered that if a node can always "exit" in any way, the sharing will be unfair or worse, no beacon master is available. Thus, in at least one embodiment of the present disclosure, if the mechanism allows a node to "exit" fulfilling the beacon master role, the participating nodes are provided with incentives, such as giving them respective priority over the communications of the non-participating nodes.

Fig. 25A-25E illustrate an example embodiment 350 of a main beacon interrupt process, which will be described in detail at the end of the next section.

4.5.3.1, random primary beacon allocation

Fig. 26A and 26B illustrate an example embodiment 390 of a protocol for deploying random active beacon selection. The routine begins by waiting at 392 in fig. 26A to receive a peer beacon and then modifying the primary beacon select variable, here depicted by decrementing 394 the primary beacon countdown value, and then checking whether the value has reached zero, indicating that the new primary beacon being checked should be in an active state. If the current primary beacon is still active, execution returns to block 392. Otherwise, based on checking which node the last beacon master previously communicated as the next (successor) beacon master, a check 398 determines whether the node is the new primary beacon. If it is not a new primary beacon, execution returns to block 392 to wait for receipt of a peer beacon. Otherwise, if the node is to become a new primary beacon, the node declares itself a primary beacon and selects the following primary beacon, here exemplified by using random pick 400 and setting a countdown timer. It should be appreciated that in at least one embodiment, other mechanisms may be used to select the next primary beacon in addition to random selection.

Continuing in fig. 26B, the master beacon performs its duties 402 including sending discovery beacons and peer activities including sending peer beacons and receiving other peer beacons, and then updates 404 the master beacon countdown, e.g., by decrementing it according to this example. It is checked if the primary beacon service period has ended (primary beacon counter 0)406 and if not execution returns to block 402 with the current primary beacon still performing its duties. Otherwise, a check is performed 408 whether a peer beacon reports a new primary beacon. If a peer beacon reports a new primary beacon, execution returns to the beginning of the routine at block 392 in FIG. 26A, else decision block 410 is reached to check if the new primary beacon timer has expired. If the time has expired, execution returns to block 400 in FIG. 26A, where the node again declares itself a beacon master and selects a successor master beacon. Otherwise, if the timer has not expired, execution returns to decision block 408 to check again.

Thus, the above flowchart shows the process of the current master beacon determining which node will become the next master beacon. Each mesh node has a list of other mesh nodes that it can reach through one or more hops. In this example, the selection of the next primary beacon occurs randomly from the list of reachable nodes. The current master beacon forwards information about the current and future master beacons to all mesh nodes in the network through the peer-to-peer beacons and the discovery beacons. The current primary beacon has a countdown field to indicate when to stop transmitting discovery beacons and when to start a new primary beacon. Each node that receives a peer beacon from the master beacon will decrement the countdown timer and forward the updated countdown value to its peer and send the current beacon master ID and the next beacon master information to its peer through its peer beacon. This will ensure that the information is spread throughout the network.

The countdown timer should be synchronized throughout the network. Each node should adjust the count down relative to a fixed time and if the counter passes that time, it should be decremented. This configuration is used to solve the problem when more than one BI is used across the mesh network. If all mesh nodes have the same BI, each node should decrement its countdown timer with each beacon transmission. When the counter reaches zero, the current master beacon stops sending discovery beacons and assumes that the new master beacon will take over.

4.5.3.1.1, managing New Master Beacon interrupts

The new primary beacon should start sending discovery beacons and send peer beacons to account for the primary beacon rules in the transmitted beacons. Other nodes in the network will continue to send peer beacons with primary beacon IDs that complete their tasks with a countdown timer equal to zero until a new primary beacon with a new timer advertisement is received either by the new primary beacon or by one of the peer nodes.

The master beacon that completes its task will wait to receive the signal that the new beacon master takes over. This should be done by receiving a peer beacon from one of its peer nodes indicating that the current primary beacon is one previously selected by the primary beacon that completed its task.

In fig. 25A-25E, process 350 is outlined for the case where a primary beacon that has completed its primary task does not receive any indication that a new primary beacon started its task. Thus, the original master beacon will again declare the master beacon role for another master beacon period and select a new node as the next master beacon.

In the figure, nodes MSTA a 352, MSTA B354, MSTA C356, MSTA D358 and MSTA E360 are interconnected. In fig. 25A, MSTA a 352 is a beacon master that transmits discovery beacons in all relevant directions 362 in scan 364. The peer beacon 366 provides information about the current Beacon Master (BM) which is MSTA a, the next beacon master a is exemplified as MSTA C356, and the BM counter is x. In fig. 25B, peer beacon 368 indicates that the BM counter has reached 0 and MSTA a 352 is waiting 370 for MSTA C356 to begin acting as a beacon master. However, in this case, the communication link with MSTA C is broken, or MSTA C is inactive or willing to fulfill the BM role. In fig. 25C, nodes MSTA B, MSTA C, MSTA D, and MSTA E are still sending peer beacons 368 indicating that the BM counter is 0 for MSTA C to fulfill the BM role. Then, after waiting for the timeout of MSTA C to take on the BM role, the current BM then proceeds to 372 to continue fulfilling the BM role and sends a peer beacon indicating the next BM as MSTA E and sends the counter x. In fig. 25D, the far peer beacon 376 still indicates that the BM counter is 0, waits for MSTA C to be a BM, but MSTA a has already taken on BM role 374, and is sending a peer beacon indicating the next BM to be MSTA E and decrementing the BM counter. In fig. 25E, the peer beacon has propagated throughout the network, and the peer beacon 378 currently from MSTA a 352 indicates that the next BM is updated to x-2 as MSTA E and BM counter.

4.5.3.1.2 Beacon Master selection update element

After a new node is added to the network, the selection list in each mesh node will be updated to allow the new node to be selected at some point to act as a beacon master. The master beacon may add the node to the list via a message flooding the network indicating that the list of mesh nodes has been updated. The node software (protocol) can also do this by forcing the latest master beacon to help the new node to select the new node to act as a master beacon immediately upon admission to the network. The node will note that the new node acts as a beaconing master and should update its mesh node list.

When a node leaves the network, the selection list in each mesh node is updated to remove the new node from the list, and therefore is not selected as a beacon master at some point. This node deletion operation may be performed using network message flooding that indicates that the list of mesh nodes is updated or may be distributed by monitoring the behavior of the nodes in the network. If a node fails to act as a beacon master for multiple discovery service periods, it will be removed from the list.

4.5.3.2 sequence-based Primary Beacon Allocation

Fig. 27A and 27B illustrate an example embodiment 430 of a protocol (process) for deploying sequence-based primary beacon selection. The sequence determines the order of nodes switching the beacon master role and updates each time a new mesh node is added. The routine begins at 432 to wait for receipt of a peer beacon, thereafter updates the master beacon counter 434 (decrementing by way of example as shown), and performs a counter threshold check 436 to determine if the counter has reached a terminal value, in this example zero. If the terminal count has not been reached, execution returns to waiting at block 432. Otherwise, if the count has expired, a check is made 438 whether the node is a new primary beacon. If not, execution moves to block 448 in FIG. 27B. If it is a master beacon, 440 declares the node as a master beacon and sets the counter for its duration as the master beacon, and then performs master beacon responsibilities 442, such as sending discovery beacons and their peer responsibilities in sending and receiving peer beacons. The master beacon counter is then updated 444, counting down in this example, and a check is made at step 446 as to whether the end of the count, which in this example is zero, has been reached. Execution returns to block 432 if the end of the count has been reached, otherwise execution returns to perform another round of primary beacon responsibility 442. As seen at block 448 in fig. 27B, a check is made to determine if a peer beacon with a new MB tag has been received. If a new MB tag is received, execution returns to wait at block 432 in fig. 27A, otherwise execution waits 450 to receive a peer beacon with a new master beacon tag and a non-terminal (in this example non-zero) counter. A check 452 is then made on the new master beacon timer as to whether the time has expired. If the new master beacon timer has not expired, execution returns to block 448 to check for peer beacons with new MB tags, otherwise execution moves to check 454 whether the node is the next master beacon after the failed node. If the node is not a new master beacon, execution returns to block 448 to check for peer beacons with new MB tags. Otherwise, the node is the new beacon master, and execution returns to block 440, where the node declares itself a new primary beacon and begins processing as such.

It will be noted that each time a new node joins the network, the current master beacon is responsible for updating the sequence and informing the network mesh nodes of the update. Once each node knows the sequence and the currently active beacon master, it will be able to know the next beacon master and when it occurs. The BM count is forwarded by the mesh node to mark the start and initiation of the beacon master discovery period.

In at least one embodiment, the BM counters (in this example, the countdown timers) are synchronized throughout the network. Each node should adjust the count down relative to a fixed time and if the counter passes that time, it should be decremented. This should solve the problem when more than one BI is used across the mesh network. If all mesh nodes have the same BI, each node should decrement its countdown timer with each beacon transmission.

Once the timer reaches its termination condition, e.g., zero in the illustrated example, the mesh node knows that new beaconing is taking over. If the mesh node is the new beacon master, it starts sending discovery beacons and sets the BM counter value. The current master beacon forwards information about the current and future master beacons to all mesh nodes in the network through the peer-to-peer beacons and the discovery beacons. The beacon of the current primary beacon transmission has a counter field to indicate when the discovery beacon will stop being transmitted and when a new primary beacon should start.

Each node that receives a peer beacon from a master beacon modifies the BM counter to a terminal value, e.g., decrements the countdown timer, and forwards the updated BM counter value along with the current beacon master ID and sequence ID to its peer through its peer beacon to ensure that this necessary information is propagated throughout the network. The new primary beacon starts sending discovery beacons and sends peer beacons to account for the primary beacon rules in the sent beacons.

4.5.3.2.1, managing New Primary Beacon interrupts

If after a waiting period the new master beacon does not start to function, the next master beacon in the sequence should take over and assert the master beacon rule, set the counter and start to notify the mesh node.

4.5.3.2.2 Beacon management hopping sequence update element

The beacon master is responsible for updating the order of the beacon master nodes. The update should be the result of a new node joining the network or a node leaving the network. The assigned information may be in the form of a sequence ID associated with the sequence. Each node should be able to know its position in the sequence.

4.5.4, triggering discovery beacon transmission

One way to implement discovery of beacons is to trigger it whenever there is a new event in the network. This means that it is found that the transmission of beacons need not be periodic. This event may be the new node sending a probe request that the mesh node receives, the mesh node losing connectivity, or any other event that requires a full scan of beacons or similar frames in all directions for discovery and beamforming reasons. This event may trigger one or more mesh nodes to transmit discovery beacons.

4.6 finding a mesh map

Mesh nodes listen during periods of inactivity (no transmission or reception) and scan for new nodes attempting to join the network. The nodes may listen in a quasi-omni mode so that all directions can be scanned simultaneously, although the range is limited. Then, in order to increase the range over which the mesh node scans for new nodes, in at least one embodiment, directional antenna operation is selected by the system. Typically, using directional antennas involves the process of each node scanning all directions.

However, if the node topology includes a dense network deployment, the node coverage will likely overlap, and at least one embodiment of the present disclosure then coordinates the area where each node will perform a scan for new nodes, thereby more efficiently covering the geographic area.

Fig. 28 illustrates an example embodiment 470 where each node is responsible for one or more particular directions, which will be continuously and individually monitored as long as the node is not transmitting or receiving. This will help to concentrate on making nodes available in one direction, rather than being distributed in all directions. In this example, the discovery graph is created by the cooperation of nodes (where each node is assigned one or more specific directions for monitoring and scanning). The discovery map may be generated using measurement activity collection, topology information of the network, or some antenna pattern analysis.

In the example shown in fig. 28, the example mesh node MSTA a 472 is shown as allocation regions 474a and 474B, the mesh node MSTA B476 is shown as allocation regions 478a and 478B, the mesh node MSTA C480 is shown as allocation regions 482a and 482B, the mesh node MSTA D484 is shown as allocation region 486, the mesh node MSTA E488 is shown as allocation region 490, the mesh node MSTA F492 is shown as allocation region 494, and the mesh node MSTA G496 is shown as allocation region 498. Thus, each mesh node is responsible for a particular area (direction) to scan when making any other transmission or reception with other nodes in its network.

In at least one embodiment of the present disclosure, analyzing cell plans is based on estimating at each area what the potential mesh nodes covering the area are and selecting one mesh node dedicated to the area. A simple distributed method of determining sector coverage areas is to allow sectors that are in line of sight and can listen to each other's transmissions to turn off one of them and consider the other to cover all of its coverage areas.

Fig. 29A-29C illustrate an example embodiment 510 of determining a new node coverage area. In each figure, MSTAA 512 and MSTA B514 are shown as directional antenna sectors 516a (S1) through 516d (S4) and 518a (S1) through 518d (S4), respectively.

In fig. 29A, MSTA a 512 and MSTA B514 are in line of sight, and it is assumed that any node between these nodes can be reached through one of the two direction sectors, since direction 516a (S1) of MSTA a 512 can communicate with direction sector 518c (S3) of MSTA B514. Thus, each of these sectors may declare this coverage as its discovery zone.

In fig. 29B and 29C, the intended coverage areas 520 and 522 for MSTA a and MSTA B, respectively, are seen. In this embodiment, the present disclosure determines the region based on the collected measurements. In this example, mobile stations and other stations connected to the mesh network are collecting information about their location and which nodes can be seen. These lists are processed together to form the relationship between them. The result is an estimate of the potential coverage area of each sector. The more sites in the network, the more accurate the estimation of the coverage area of these node sectors. Likewise, as a node moves and discovers a new node, an update with the discoverable new node/sector set will be sent. The mobile node is discovering and making invisible other nodes and forms a new list of neighbors that can be seen at the same time. These lists will be kept and processed periodically.

In at least one embodiment, a centralized procedure is employed in which nodes send location reports and discovered sector lists to a central entity. The central entity collects all lists from all network nodes and forms a discovery map. The central entity sends the scan to each node and notifies it of the discovery zone after processing the collected list. Once the node location or discovered sector changes, the node may periodically or briefly send a report of all lists collected over a period of time to update network information.

4.7 New node discovery

The system is configured so that a new node can search for nodes and discover neighbors in the network using passive or active scanning. A new node that passively scans for neighbors is looking for beacon master beacons. Nodes in the network do not send beacons simultaneously and each node in the network has the opportunity to act as a beacon master. Once the new node acts as a beacon master, the beacon should be heard from nearby nodes.

4.7.1, fully passive New node Scan

In at least one embodiment, the new node may connect to the mesh network using only passive scanning. This approach is applicable to nodes that do not have the time requirement to connect to the network or discover all neighbors. This is performed according to at least two different embodiments.

4.7.1.1 waiting for a beacon master beacon

The new node waits for all neighboring nodes to act as master beacons and receive its beacons. After receiving the first primary beacon, the new node should have completed the scanning period after a period of time equal to the total number of nodes multiplied by the discovery period (primary beacon service period). If the node only adjusts to passive scanning, then in a sequence-based beacon master switch, when the new node receives the same beacon again, it will know that the scanning period has ended. According to this embodiment, the new node is configured to then contact the current primary beacon for inclusion in the primary beacon interval. The current master beacon should update the master sequence of beacons or the list of mesh nodes in each mesh node. The discovery period may be adjusted so that connection delays can be tolerated for new node joining. The new node may scan with a quasi-omni or directional antenna.

4.7.1.2, triggering New node Admission

In this embodiment, new node admission is triggered in response to receiving a beacon from a beacon master. The new node is waiting for a beacon from the current master beacon. Upon receiving the beacon, a new node admission protocol is triggered. The new node is listening for the primary beacon at all times. If the node only adjusts to passive scanning, then in a sequence-based beacon master switch, when the new node receives the same beacon again, it will know that the scanning period has ended. In this embodiment, the new node is configured to contact the current master beacon to begin the node admission sequence. The current master beacon should update the beacon master sequence or the list of mesh nodes in each mesh node. The neighbors of the new node will start sending beacons in sequence and declare the temporary beacon master role. The discovery period may be adjusted so that connection delays can be tolerated for new node joining. The new node may scan using a quasi-omni or directional antenna.

4.7.2 Passive/active New node Scan

The new node may look up the beacon from the current beacon master starting with the passive scan. If a node receives a beacon from the current beacon master, it will inform the beacon master of its presence and the current beacon master triggers a new node admission protocol. If the new node does not receive any beacon, it will send a probe request from a quasi-omni antenna or multiple probe requests in each direction. Once the mesh node receives the probe request, it will respond with a probe response and inform the current beacon master of the new node's presence. The current beacon master will trigger a new node admission protocol. The new node may decide to send the probe request directly without looking for a beacon master to reduce connection time.

4.7.3 New node license agreement

Once the beacon master is notified that a new node exists, it will trigger a new node admission protocol. If the new node receives a discovery beacon from a beacon master, the new node may inform the current beacon master itself and may communicate directly with the beacon master. When other mesh nodes receive probe requests from the beaconing master, they may inform the current beaconing master of the presence of the new node. The beacon master schedules activities to help the new node join the network. This is performed by interrupting the currently scheduled sequence of beacon masters or future allocations and scheduling nodes around the new node to act as beacon masters for a period of time equal to or less than the discovery period.

Each node stores a list of nodes in its geographic discovery graph. The list includes nodes that are potential neighbors of the neighbor or any new node discovered by the node. The nodes in the geographical discovery map of the mesh node that discover the new node act as beacon masters and transmit discovery beacons in all directions in sequence. After discovering the first mesh node, the new node is listening for more discovered nodes for a selected period of time. For example, a new node may discover one or more nodes in a geographic discovery area that are scheduled to act as beacon masters and mesh nodes that discover the new node for the first time. After the new node discovery timer expires, the new node will end its neighbor discovery and scanning process. The new node selects a neighbor to connect to and establishes a connection with the mesh network. The beacon master selection process then returns to normal operation and continues with the sequence of future selections before the new node approves the agreement. The new node listens for peer-to-peer beacons to determine the current primary beacon. If a discovery beacon needs to be sent, the new node sends a request to the primary beacon to serve as a future primary beacon. The master beacon processes the request and adds a new node to the current sequence, or updates the MB node list in each mesh node. The primary beacon determines the discovery beam to be used and whether a discovery beam is needed. In at least one embodiment, the following procedure may be performed with a centralized entity reachable by any node other than the primary beacon: scheduling a new primary beacon to assist the new node, adding the new node to a sequence or list of future possible primary beacons in the node, and determining a discovery direction of the node.

The new node may continue to listen long enough to ensure that all nearby nodes have had an opportunity to act as beacon masters and thus all neighbors have been discovered, or may request the mesh node to expedite the discovery process by triggering a new node admission protocol. However, if there are many nodes in the network, or the master beacon service interval is long, the process of waiting for one of the nearby nodes to act as a beacon master can be time consuming.

Fig. 30 is an example embodiment 530 of new node admission in response to passive scanning within a BM coverage area. The figure shows communication between the new node 432, the neighbor 1 node 534, the neighbor 2 node 536, the neighbor 3 node 538, the beacon master 540, and the mesh node 542. A Beacon Master (BM) triggers a sequence to change BMs to assist new nodes to join the network quickly. The BM sends BM scheduling updates to force other nodes around the new node to send discovery beacons. When the new node 532 transmits discovery beacons in all directions 544, 548 and 546, the new node 532 listens for discovery beacons transmitted from the beacon master 540. In this example, when the new node 532 receives the discovery beacon 544, it is within range of the beacon master 540 to which the response 550 is sent. The current beacon master 540 advertises 552 beacons 554, 556, 558, 560, 561. In some cases, the beacon master sends a schedule and some information 561 to help the new node also find neighbors. The new node receives discovery beacons 568 from the new beacon master neighbor 3 node 538, which the master neighbor 3 node 53 transmits in all directions 562, 564, 566. The new node responds 570 with a beacon response. Similarly, discovery beacons are sent by the subsequent beacon master neighbor 2 node 536 in all directions 572, including directions 574, 576 and 578. The discovery beacon is then sent by the subsequent beacon master neighbor 1 node 534 to which the new node sends a beacon response 588 in all directions 580, including directions 582, 584, and 586, followed by a registration request 590 to join the network. The beacon master then updates the beacon master schedule and sends it out 594, 596, 598, 600, and 602 to all nodes.

Fig. 31 illustrates an example embodiment 610 of new node admission in response to an active scan within a BM coverage area. The figure shows communication between a new node 612, a neighbor 1 node 614, a neighbor 2 node 616, a neighbor 3 node 618, a beacon master 620, and a mesh node 622. One BM is active but when a new node is detected the BM sequence changes to add a neighbor node to the new node to speed up the discovery process.

As can be seen above, in accordance with embodiments of the present disclosure, a node may choose to actively search for neighbors by sending probe requests in all directions or using a quasi-omni antenna. The new node receives a probe response from one of the mesh nodes in response to its probe request, triggering a new node admission protocol to join (kick in). The new node admission protocol interrupts the current primary beacon or the next primary beacon selected by the current sequence and forces the neighbor nodes of the new node to be used as primary beacons in turn, so that the new node has an opportunity to quickly discover nearby neighbors. The determination of possible neighboring mesh nodes may be performed by defining a geographical discovery map for each node or sector. The geographical discovery graph for each node or sector represents a list that defines potential neighbor nodes/sectors if the node or sector discovers a new node. After the new node discovers all neighbors and connects to the mesh network, the current master beacon is responsible for adding the new node to the available node list or master beacon sequence list of each node, depending on the master beacon selection method used in the mesh.

4.7.4 geographic discovery zone

A geographical cluster of nodes is created for each MSTA or MSTA sector. For each node sector, the area covered by the sector represents the sector's footprint. A set of possible neighboring nodes or node sectors that may be found in the sector's footprint includes a geographical discovery node or sector set. The set contains nodes or sectors that may be seen by the sector or any new node found in the sector. Not all members of the set should be discovered by the new node, but it represents all possible potential neighbors. In at least one embodiment, the set is updated each time a new node joins the network to include a newly joined MSTA. This set may be constructed using measurement activity collection, network topology information, or some form of antenna pattern analysis.

Fig. 32 illustrates an example embodiment 710 of a node or sector geographic discovery set (sector coverage area). The figure depicts node MSTA a712 having sectors 718a through 718d, MSTA B714 having sectors 720a through 720d, and MSTA C716 having sectors 722a through 722d, depicting the antenna direction sectors they overlap. As can be seen in the figure, any node discovered by MSTA a712, sector 3(S3)718C may have MSTA C716 (S1)722a and (S2)722B and/or MSTA B714 (S4)720d as neighbors. Any node discovered by MSTA B714 (S1)720a will only have MSTA a712(S2)718B as a potential neighbor. The formation of the geographical discovery zone may be performed by the system through measurement reporting in the network or with an analytical cell planning procedure.

In at least one embodiment, analyzing the cell plan is based on estimating potential neighbors at each coverage area of a node sector and loading a list to the node sector. To generate this list from measurement reports, a centralized or distributed process may be used. Each node/sector maintains a list of neighboring nodes/sectors that can be discovered by the node/sector. These lists are processed together to form the relationship between them and, if the sector is found, results are produced that estimate the potential neighbors of each sector. The more nodes present in the local network, the more accurate the result estimation of the discovery zone. In addition, as nodes move and discover new nodes, updates will be sent using the discoverable new node/sector set. The mobile node is being discovered and not seen by other nodes, which form a new neighbor list that can be seen at the same time. These lists will be kept and processed periodically.

In a centralized process, a node sends a neighbor list for each sector to a central entity. The central entity collects all lists from all network nodes and forms a geographical discovery zone. The central entity, after processing the collected list, sends a set of geographical discovery areas to each node. In at least one embodiment, once the neighbor list changes, the node sends reports (periodically or temporarily) of all lists collected over a period of time to update the network information.

In a distributed process, a node sends each of these lists to all members of the lists. In at least one embodiment of this case, the list is sent to all members of the list at the moment it is updated, before the node does not see any list members. A node receiving a list from another node will add all members of the list to the discovery zone of the sector received from it.

Fig. 33 shows an example embodiment 730 that is a variation of the situation shown in fig. 32, depicting a situation where a node moves and forms a new list. As shown, these lists are used to update the geographical discovery zones set for these neighbors. The figure depicts node MSTA a712 having sectors 718a through 718d, MSTA B714 having sectors 720a through 720d, and MSTA C716 having sectors 722a through 722d, depicting the antenna direction sectors they overlap. As shown, the mobile node moves through the antenna sectors associated with the three fixed nodes, with intermediate positions 740a through 740f for the mobile node. A new list is created when the neighbor association changes from MSTA a712 (S4) to the only neighbor of L1740a, to neighbors MSTA a712 (S4) and MSTA C716 (S1) to L2740B, to only neighbor MSTA C716 (S1) to L3740C, to MSTA a712 (S3) and MSTA C716 (S1) to L4740 d, to MSTA a712 (S3), MSTA C716 (S1) and MSTA B714 (S4) to L5740 e, and finally to MSTA a712 (S3) and MSTA 714B 714(S4) to L6740 f.

Table 1 details the neighbor list and discovery zone updates for each of the mobile node locations L1 through L6 for the example of fig. 33.

4.7.5 New node discovery protocol

Fig. 34A and 34B illustrate an example embodiment 750 of a process for a new node to discover and join a mesh network. The process starts 752 and the new node search waits 754 for a beacon to be found, e.g., within a certain period of time equal to X. The timer may employ a number of values to define various modes of operation. In block 756, the discovery beacon received from the primary beacon is checked. If a discovery beacon is received, execution proceeds to block 764, otherwise to decision block 758, decision block 758 checks whether the initial discovery MB timer (X) has expired. If the time period has not been completed, execution returns to block 754, otherwise it proceeds to block 760 to send a probe request, and then checks 762 if a probe response is received. If a probe request is not received, it returns to block 760 to send another probe request. Otherwise, if a response is received, it moves to block 764 to receive the discovery beacon and proceeds to check 766 in fig. 34B, which checks whether the second discovery MB timer has expired. If not, execution returns to block 764 in fig. 34A, otherwise, with the second discovery MB timer expired, a connection is established from the new node to its neighbors at block 768, then the new node registers 770 as a future MB with the MB, and the process ends 772.

In this embodiment, the following is a preferred mechanism to handle BM timing counter X. If X is equal to its maximum value, it means that the node is in a fully passive mode and will only wait for discovery beacons from the network beacon master. If X equals zero, the node will not wait for a beacon to be found, but will go directly into active scanning. If X is equal to the median value (between 0 and "infinity"), it will give the node an opportunity to receive a discovery beacon (if it is in its vicinity), otherwise it will switch to active scanning.

If a discovery beacon is found, the new node will remain in the passive scanning state and expect more discovery beacons from nearby mesh nodes. If no discovery beacon is found, the new node will switch to active scanning and send probe requests in turn from quasi-omni antennas or in all directions. When the new node receives the probe response, it will switch to passive mode and start scanning for discovery beacons. The search for discovery beacons will continue to look for a particular timer value, after which the new node will end its scan and establish a connection with the network. The new node sends a registration request to the beacon master or central controller to include it in the beacon master's future schedule.

4.7.6 BM protocol currently used to handle new nodes

Fig. 35 illustrates an example embodiment 790 of a beacon master process new node licensing procedure. The current BM is informed of the new node either by the new node responding to one of the discovery beacons sent in all directions, or by an advertisement frame forwarded to the MB through the mesh network. The beacon master updates the beacon master's future schedule and notifies the network mesh nodes. The beacon master propagates the list of nodes or new sequences to be scheduled through the peer-to-peer beacons throughout the mesh network. After a few beacon intervals, the entire mesh network should be aware of the new beacon master schedule. The current primary beacon stops sending primary beacons and the newly allocated node is taking place.

The routine begins 792 and waits 794 for a new node advertisement. After receiving the new node advertisement, it is checked 796 if the new node is responding to the discovery beacon. If the new node does not respond to the discovery beacon, block 798 is reached and it is checked whether the mesh node is advertising the new node. If the new node advertisement is not from a discovery beacon or mesh node advertisement, execution returns to block 794 to wait for the new node advertisement. Otherwise, if the new node advertisement is from a discovery beacon or mesh node advertisement, then execution proceeds to block 800, where future beacon masters are updated according to the geographic discovery zone, and block 802 is reached before the process ends 804, stopping sending discovery beacons.

4.8 centralized discovery Beacon management

In this example embodiment, the centralized entity fulfills one or more roles assigned to beacon masters. Such centralized control may facilitate the process of contacting a network controller to accommodate new nodes or to update the scheduling and scanning directionality of the network. In this embodiment, the nodes need not be aware of the current beacon master, but they should be able to communicate with the central controller. The central controller is responsible for selecting future beacon masters or update sequences, scheduling new node beacon masters, handling situations where nodes shut down or fail problems, and handling discovery maps for the network. If there is no active beacon master and there is no periodic discovery beacon transmission, the central controller is responsible for triggering the transmission of discovery beacons after certain events are detected (e.g., new nodes join or lose connection). This may include triggering one or more mesh nodes to discover beacon transmissions. The process may also include coordinating the transmission of the beacons among those mesh nodes.

Fig. 36A, 36B and 37 show example embodiments 810, 910 of network procedures for a new node allowing central controller entity coordination. In fig. 36A and 36B, the new node is outside the coverage of the beacon master, while in fig. 37 the new node is within the coverage of the beacon master.

If the new node receives a beacon from the beacon master, it will notify the beacon master and the beacon master communicates with the central controller to schedule neighboring nodes to assist the new node.

In fig. 36A and 36B, a plurality of network entities are depicted as a new node 812 seeking to join the network, a neighbor 1 node 814, a neighbor 2 node 816, a neighbor 3 node 818, a beacon master 820, a central entity 822, and a mesh node 824. Referring to fig. 36A, discovery beacons are generated 826 in all directions from the beacon master 820 to 828 the new node 812, to 830 the central entity 822 and to 832 the neighbor 816. It will be noted that these discovery beacons do not reach the new node.

Since the new node does not receive the discovery beacon, it generates 834 probe requests in all directions deemed to be 836 neighbor 2 node 816, 838 neighbor 1 node 814, and 840 neighbor 3 node 818. In response, neighbor 1 node 814 sends a probe response 842 to the new neighbor and advertises 844 the new node to central entity 822. The central entity 822 then generates an advertising beacon master schedule update 846 with advertisements 848, 850, 852, 854, and 856 directed to nodes other than the new node. When helpful, the neighbor that finds the new node sends a frame to the new node to inform the node about the new schedule and to provide some additional information that facilitates beamforming with other neighbors.

The neighbor 3 node 818 is scheduled as a new temporary beacon master and generates 858 discovery beacons in all directions 860, 862, 864.

In fig. 36B, the new node 812 generates a beacon response 866 to the neighbor 3 node 818. Neighbor 2 node 816 then generates 868 discovery beacons in all directions 870, 872, and 874. Neighbor 1 node 814 then generates 876 discovery beacons in all directions 878, 880, and 882. A potential neighbor must send a beacon in all directions to form a beam with the new node. A response is generated 884 from the new node to the best beacon of each neighbor. The new node may only receive one or perhaps a few beacons transmitted in all directions. After the new node responds, the new node sends a BM registration request 886 to the central entity 822. The central entity 822 sends 890, 892, 894, 896, 898, 900 beacon master schedule updates to all parties.

In the embodiment 910 of fig. 37, many network entities are depicted as a new node 912 seeking to join the network, a neighbor 1 node 914, a neighbor 2 node 916, a neighbor 3 node 918, a beacon master 920, a central entity 922, and a mesh node 924. The beacon master 920 sends 926 discovery beacons in all directions 928, 930 and 932, which in this case arrive at the new node. New node 912 responds to beacon master 920 with a beacon response 934, and beacon master 920 advertises 936 the new node to central entity 922. The central entity then advertises the beacon master schedule to all nodes 940, 942, 944, 946, 948 except the new node 912. When helpful, the neighbor that finds the new node sends a frame to the new node to inform the node about the new schedule and some information that facilitates beamforming with other neighbors. The neighbor 3 node 918 generates 950 a discovery beacon in all directions 952, 954, 956. New node 912 responds with beacon response 958 to neighbor 3 node 918. Neighbor 2 node 916 generates 960 a discovery beacon in all directions 962, 964, 966. It will be noted that the new node is unresponsive to this and may be out of range. The neighbor 1 node 914 generates 968 discovery beacons in all directions 970, 972, 974. New node 912 responds to neighbor 1 node 914 with a beacon response 976. New node 912 sends registration request 978 to central entity 922. The central entity 922 then advertises 980 the beacon master schedule to all nodes (including the new node now scheduled as a beacon master) 982, 984, 986, 988, 990, 992.

Thus, in view of the above, it can be seen that if a new node finds a neighbor node by sending a probe request and a received probe response, the neighbor node will communicate with the central controller to schedule the neighbor node to assist the new node. The central controller updates the beacon master schedule to assist the new node and manages back to the previous schedule when the new node license agreement is complete. After the new node connects to the network, it may send a registration request to the central controller to include it in future beacon master schedules and adjust its discovery scan. The central controls the response by updating the network beacon master schedule and discovery scan map for the entire network.

4.9 efficient mesh collaboration for new node neighbor discovery

Once the mesh nodes are informed of the presence of a new node through passive or active scanning, the mesh coordinates the discovery process between the mesh nodes. The nodes are arranged to transmit their network advertisement frames in all directions during a Data Transmission Interval (DTI) period, which has the same function as the discovery beacon, but can be transmitted in the DTI period. Each mesh node repeats the transmission of beacons for a number of periods depending on the capabilities of the new node. After the mesh node completes, the new mesh node starts sending its advertisement frame. At the end of the transmission period of each announcement frame, in each antenna sector, a time slot is allocated for the SSW frame exchange. In at least one embodiment, the peer link establishment is reserved for a period of time at the end of the transmission of all cycles and SSW slots. In beacon transmission in regular frames, peer beacons and allocated SSW slots are added and dedicated to the new node with MSTA B if the new node is already connected to the mesh node.

Fig. 38A and 38B depict an example embodiment 1010 of the above-described process between MSTA a 1012, MSTA B1014, and MSTA C1016. In fig. 38A, beacons 1030, 1032, 1034 are seen, preceded by an ABFT and DTI period before the secondary discovery period 1018 beacon. In this secondary discovery period, broadcast frames 1022, 1024, 1026 are seen, between which is an SSW frame exchange 1020, followed by a possible link establishment slot 1028. In fig. 38B, beacons 1036, 1038, 1040 are transmitted, followed by ABFT and DTI communications.

This technique will avoid any interruption of the beaconing master exchange protocol used in the mesh network, where no beaconing master needs to be exchanged to assist the new node in the protocol.

4.10 simplified high efficiency beacon mode

In this section, a simple mode of operation will be described. The mesh nodes are assigned primary beacon roles in a periodic order. Each mesh node is allocated a time to start transmitting a discovery beacon, the number of beacons acting as beacon masters (discovery period) and a period to repeat its role (master beacon interval). A central entity or mesh node may be responsible for managing this operation. Some information may also be defined in the mesh profile (discovery period and primary beacon period) if there is no central entity. The mesh node may randomly select a time from a predefined time slot or through channel sensing to start its discovery period.

When a new node attempts to join the mesh network, it may passively listen for the master beacon interval to receive all beacons transmitted in different discovery periods. A form of mesh assistance may be applied by coordinating between mesh nodes after a mesh node discovers a new node. As shown in fig. 38A and 38B, this is to transmit a beacon in the DTI period by the scheduling node. Another form of assistance is to force the new node to send probe requests in all directions and to force the mesh nodes to listen for probe requests from the new node.

4.11 New frame Format

4.11.1 Beacon response

This frame is needed when a new node (STA) uses passive scanning and finds a beacon. The new STA sends a beacon response to inform the discovered STAs of its presence. This framework can also be used to trigger beamforming training if desired. In at least one embodiment, the frame of the assistance request message contains the following information: (a) NSID-indicates a new STA to assist; (b) SSID/SSID list-a list of SSIDs that provide new STAs to attempt to connect to; (c) DMG function-indicating functions supported by the new STA; (d) mesh ID-mesh identification element; (e) assistance request flag-indicating whether a new STA is requesting mesh discovery assistance; (f) beamforming training request-indicating whether a new STA is requesting beamforming training; (g) beacon ID-MSTA discovery beacon ID; (h) beam ID-in case of a directional transmission beacon response message, the beam ID is transmitted; (i) message counter-message counter if a frame is sent multiple times from an omni/quasi-omni antenna.

4.11.2 Beacon response ACK

In the case of passive scanning, this message frame is sent from the discovered MSTA to the new STA to acknowledge receipt of the beacon response message and set the mesh discovery assist phase. In at least one embodiment, the frame of the beacon response ACK message contains the following information: (a) assisted acknowledgement-providing mesh assisted acknowledgement; (b) new STA best transmit beam-if the new STA sends beacon response directionally, the new STA's best transmit beam is indicated; (c) auxiliary information-auxiliary coordination information.

4.11.3 discovery beacon

This is a frame similar to a conventional 802.11DMG beacon frame, but with some elements that allow other functionality. The beacon master transmits these frames to all directions to help discover and advertise the network. The frame contains specific details for the new node to discover the network and is distinct from the peer beacons intended to synchronize and manage the mesh peers and connected STAs. If a new node finds many elements that do not require an 802.11DMG beacon, it may be deleted or considered an optional element. Once a node connects to the mesh network, it can receive all the omitted information through the peer-to-peer beacons. This is a very lightweight (low overhead) beacon and has the basic information that the node uses to discover mesh nodes, form connections and start receiving peer beacons. In at least one embodiment, the frame of the assistance response message contains the following information: (a) beacon type-discovery or peer-to-peer beacon; (b) current BM countdown timer-the countdown timer to the next BM cycle.

4.11.4 Peer-to-peer beacons

This is a similar frame to a conventional 802.11DMG beacon frame, but with some elements providing other functionality. These frames are transmitted by all nodes in their respective directions or only in their directions to their peer STAs. The beacons are used for beacon functions such as synchronization, spectrum and channel management. This information allows nodes in the network to manage the network and propagate beacon master information. Many elements of the 802.11DMG beacon may be deleted or treated as optional elements if not needed by the current mesh STA, and these elements are only used for new node discovery and mesh formation. In at least one embodiment, the frame of the assistance response message contains the following information: (a) beacon type-discovery or peer-to-peer beacon; (b) current BM ID-node ID of current beacon master; (c) BM selection criteria-random or sequence based; (d) future BM ID or BM sequence-specifies the next BM ID or BM sequence number; (e) current BM countdown timer-the countdown timer until the start of the next BM cycle; (f) extended beacon master information-if it has a value, indicating that more information is attached to the peer beacon to assist BM updates; (g) discovery period-the number of BIs forming a discovery period; (h) beacon master interval-the number of BIs forming a beacon master interval. If extended beacon master information is defined, the beacon contains some information elements that are required to form certain actions.

4.11.4.1 New node advertisement message

This information element is used to inform the current beacon-master network that there is a new node discovered by a mesh node. The node that finds the new node forms this element and other nodes forward it to the current BM. In at least one embodiment, the frame of the assistance response message contains the following information: (a) new node ID-discovery or peer-to-peer beacon; (b) discovery node ID-node ID of current beacon master; (c) discovery node sector ID-the sector of the node that discovers the new node; (d) new node function-function reported by new node.

4.11.4.2 Beacon Master temporary schedule update

This information element is used to interrupt and update the schedule of the beacon master. The system may use this information element if a new node joins the network and has scheduled a discovery activity for it. In at least one embodiment, the frame of the assistance response message contains the following information: (a) number of beacon masters scheduled-the number of beacon masters that are scheduled urgently to assist the new node; (b) new node ID-node ID of new node to assist; (c) BM 1, BM 2, BM 3, … -a list of node IDs of scheduling nodes acting as beacon masters.

4.11.4.3, registration request

This is to inform the current beacon master that the new node requests registration as a future beacon master. The node may also decide not to act as a beacon master for a period of time and then switch to enable the beacon master option. The solicitation flag allows other nodes to schedule the node for future discovery cycles. In at least one embodiment, the frame of the assistance response message contains the following information: node ID-ID of the node that needs to be registered as a BM in the future.

4.11.4.4 Beacon Master Schedule update

This is to inform nodes in the network about new ones of the steady state beacon master handover updates. This may take the form of adding a new node or removing a node from the current node list or current sequence. In at least one embodiment, the beacon master schedule includes the following fields: (a) number of nodes to update-number of beacon masters added or deleted from the list or sequence; (b) new node ID-the node ID of the node to be added or deleted from the node list or sequence; (c) action-add or delete nodes; (d) new sequence-a new update sequence of the list after adding or deleting a new node.

5. Summary of the invention

A wireless communication system/apparatus/method with directional transmission that performs transmission of a signal that facilitates scanning a mesh network to discover and maintain links between peer STAs in the mesh network, comprising: (a) a STA transmitting beacons of a first type to maintain existing links in one or more neighboring peer STAs, wherein (a) (i) the beacons of the first type contain time synchronization and resource management information; (a) (ii) the STA transmitting beacons of the first type with a reduced number of antenna sectors; (b) the STA transmitting a second type of beacon to assist in network discovery of the newly joined STA, wherein (b) (i) the second type of beacon contains mesh network profile information for identifying the operating network; (b) (ii) the STA transmits the second type of beacon with coordination among other STAs in the network.

In addition to the above, in at least one embodiment, an STA that is searching for nearby available networks performs an active scan or a passive scan, the STA signaling network discovery intent.

In addition to the above, in at least one embodiment, upon receiving a signal informing of an intention of network discovery, one or more STAs in an existing network schedule transmission of discovery beacons to STAs seeking available networks.

In addition to the above, in at least one embodiment, the STA that receives the signal informing the network of the network discovery intention transmits a subset of the received information to a scheduling entity of the network, the scheduling entity of the network collects information from the STAs in the network, determines a transmission time of the discovery beacon and the transmitting STA, and informs the transmitting STA of the transmission time of the discovery beacon.

In addition to the above, in at least one embodiment, the STA receiving the transmission time of the discovery transmits a discovery beacon as indicated by the received information.

In addition to the above, in at least one embodiment, a STA collects information about a newly joined STA from its neighboring peer STAs and determines the transmission timing of a discovery beacon and transmits the discovery beacon according to the determination.

In addition to the above, in at least one embodiment, the mesh STA may coordinate transmission of network advertisement frames in all directions to the new node during the data transmission period to facilitate fast neighbor discovery.

The enhanced functionality described in the present technology can be readily implemented in a variety of millimeter wave transmitters, receivers and transceivers. It will also be appreciated that modern transmitters, receivers, and transceivers are preferably implemented to include one or more computer processor devices (e.g., CPU, microprocessor, microcontroller, computer-enabled ASIC, etc.) and associated memory storing instructions (e.g., RAM, DRAM, NVRAM, FLASH, computer-readable media, etc.) so as to execute the programming (instructions) stored in the memory on the processor(s) to perform the steps of the various processing methods described herein.

For simplicity of illustration, the computer and memory devices are not shown in the figures, as one of ordinary skill in the art will recognize that steps associated with various modern communication devices may be performed using computer devices. The presented techniques are non-limiting with respect to memory and computer readable media, as long as they are non-transitory and, thus, do not constitute transitory electronic signals.

It should also be understood that the computer-readable medium (the memory storing the instructions) in these computing systems is "non-transitory," including any and all forms of computer-readable medium, with the sole exception being a transitory, propagating signal. Thus, the disclosed technology may include any form of computer-readable media, including those that are random-access media (e.g., RAM), media that require periodic refreshing (e.g., DRAM), media that degrade over time (e.g., EEPROMS, magnetic disk media), or media that store data only for a short period of time and/or only upon power-up, the only limitation being that the term "computer-readable media" is not applicable to electronic signals in the transient state.

Embodiments of the present technology may be described herein with reference to flowcharts and/or flowcharts of processes, algorithms, steps, operations, formulas or other computational descriptions of methods and systems according to embodiments of the technology, which may also be implemented as computer program products. In this regard, each block or step of the flowcharts, and combinations of blocks (and/or steps) in the flowcharts, and any process, algorithm, step, operation, formula, or computational description can be implemented by various means, such as hardware, firmware, and/or software, including one or more computer program instructions embodied in computer readable program code. It will be understood that any such computer program instructions may be executed by one or more computer processors, including but not limited to a general purpose computer or special purpose computer or other programmable processing apparatus to produce a machine, such that the computer program instructions which execute on the computer processor or other programmable processing device create means for implementing the specified functions.

Accordingly, the blocks of the flowcharts, as well as processes, algorithms, steps, operations, formulas or computations described herein, describe combinations of means for performing the specified functions, combinations of steps for performing the specified functions and computer program instructions, e.g., program instructions, embodied in computer-readable program code logic means for performing the specified functions. It will also be understood that each block of the flowchart illustrations, and any process, algorithm, step, operation, formula, or computational description and combinations thereof described herein can be implemented by special purpose hardware-based computer systems which perform the specified functions or steps, or by combinations of special purpose hardware and computer readable program code.

Furthermore, these computer program instructions (e.g., instructions contained in computer-readable program code) may also be stored in one or more computer-readable memories or memory devices that can direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memories or memory devices produce an article of manufacture including instruction means which implement the function specified in the flowchart block or blocks. The computer program instructions may also be executed by a computer processor or other programmable processing apparatus to cause a series of operational steps to be performed on the computer processor or other programmable processing apparatus to produce a computer implemented process such that the instructions which execute on the computer processor or other programmable processing apparatus provide steps for implementing the functions specified in the flowchart, program, algorithm, step, operation, formula or calculation description.

It will also be appreciated that the term "programming" or "executable program" as used herein refers to one or more instructions that may be executed by one or more computer processors to perform one or more functions as described herein. The instructions may be embodied in software, firmware, or a combination of software and firmware. The instructions may be stored locally to the device in a non-transitory medium or may be stored remotely on a server, e.g., all or a portion of the instructions may be stored locally and remotely. The remotely stored instructions may be downloaded (pushed) to the device by user initiation or automatically based on one or more factors.

It will also be appreciated that as used herein, the terms processor, hardware processor, computer processor, Central Processing Unit (CPU), and computer are used synonymously to refer to a device capable of executing instructions and communicating with input/output interfaces and/or peripheral devices, the terms processor, hardware processor, computer processor, CPU, and computer are intended to encompass single or multiple devices, single and multiple core devices, and variations thereof.

From the description herein, it is understood that the present disclosure includes a number of embodiments, including but not limited to the following:

1. an apparatus for wireless communication in a mesh network, the apparatus comprising: (a) wireless communication circuitry configured to wirelessly communicate with other wireless communication stations using directional transmissions having a plurality of antenna pattern sectors each having a different transmission direction; (b) a processor coupled to the wireless communication circuitry; and (c) a non-transitory memory storing instructions executable by the processor; (d) wherein the instructions, when executed by a processor, perform the steps of: (d) (ii) (i) transmitting a peer beacon comprising time synchronization and resource management information, which is a first type of beacon, to maintain existing links between one or more neighboring peer stations within the mesh network; and (d) (ii) transmitting a network discovery beacon, which is a second type of beacon, containing mesh profile information identifying the mesh network to assist in network discovery for wireless communication stations to join the mesh network.

2. An apparatus for wireless communication in a mesh network, the apparatus comprising: (a) wireless communication circuitry configured to wirelessly communicate with other wireless communication stations using directional transmissions having a plurality of antenna pattern sectors each having a different transmission direction; (b) wherein the directional transmissions facilitate scanning a mesh network to discover and maintain links between peers in the mesh network; (c) a processor coupled to the wireless communication circuitry; (d) a non-transitory memory storing instructions executable by a processor; (e) wherein the instructions when executed by a processor perform the steps of: (e) (ii) (i) transmitting a peer-to-peer beacon, which is a first type of beacon, including time synchronization and resource management information to maintain existing links between one or more neighboring peers within the mesh network; wherein the first type of beacon is transmitted from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on a peer location; and (e) (ii) transmitting a network discovery beacon, which is a second type of beacon, that contains mesh profile information identifying the mesh network to assist network discovery for wireless communication stations to join the mesh network, wherein the second type of beacon is transmitted after coordination among stations in the mesh network such that not all stations need to transmit the second type of beacon.

3. A method of wireless communication in a mesh network, the method comprising: (a) transmitting a peer-to-peer beacon comprising time synchronization and resource management information, which is a first type of beacon, to maintain an existing link between one or more neighboring peer stations within a mesh network of wireless communication stations utilizing directional transmission having a plurality of antenna pattern sectors, each antenna pattern sector having a different direction of transmission; and (b) transmitting a network discovery beacon, which is a second type of beacon, containing mesh profile information identifying the mesh network to assist in network discovery to join a wireless communication station to the mesh network.

4. The apparatus or method of any preceding embodiment, wherein the directional transmissions facilitate scanning a mesh network to discover and maintain links between peers in the mesh network.

5. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, perform transmitting the first type of beacon from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on peer location.

6. The apparatus or method according to any preceding claim, wherein the instructions when executed by a processor perform transmission of the second type of beacon with coordination between stations in the mesh network, whereby not all stations need to transmit the second type of beacon.

7. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: searching for available networks in the vicinity using active scanning or passive scanning, and responding to receipt of the network discovery beacon by transmitting a signal to notify an intention to join the mesh network.

8. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: transmitting a signal notifying of an intent to join the mesh network, wherein at least one station in the mesh network receiving the signal notifying of the intent to join the mesh network schedules transmission of a discovery beacon to stations searching to join the mesh network.

9. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: transmitting to a scheduling entity of the mesh network a subset of information received from stations that sent the signal notifying of the intent to join the mesh network, wherein the scheduling entity of the mesh network collects information from stations in the network, determines a transmission time and at least one transmitting station to generate the discovery beacon, and transmits to the stations a notification regarding the transmission time of the discovery beacon.

10. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: transmitting a discovery beacon in response to receiving an instruction from the scheduling entity of the mesh network to transmit a discovery beacon at the transmission time.

11. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: the method includes collecting information about a station newly joining the mesh network from its neighboring peer stations, determining a transmission timing of a discovery beacon, and transmitting the discovery beacon at the determined timing.

12. The apparatus or method of any preceding embodiment, wherein the instructions, when executed by a processor, further perform the steps of: coordinating transmission of network advertisement frames between stations in the mesh network, wherein, in response to the coordination, at least one of the stations in the mesh network transmits the network advertisement frames to a new node in all directions during a data transmission period to assist in neighbor discovery.

13. The apparatus or method of any preceding embodiment, further comprising transmitting the peer beacon from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on a peer location.

14. The apparatus or method of any preceding embodiment, further comprising transmitting the discovery beacon with coordination between stations in the mesh network, whereby not all stations need to transmit the discovery beacon.

As used herein, the singular terms "a", "an" and "the" may include the plural referents unless the context clearly dictates otherwise. Reference to an object in the singular does not mean "one and only one" unless explicitly so stated, but rather "one or more.

As used herein, the term "set" refers to a set of one or more objects. Thus, for example, a collection of objects may include a single object or multiple objects.

As used herein, the terms "substantially" and "about" are used to describe and illustrate minor variations. When used in conjunction with an event or circumstance, these terms can refer to the precise occurrence of the event or circumstance as well as the very close proximity of the event or circumstance. When used in conjunction with a numerical value, these terms can refer to a range of variation that is less than or equal to ± 10% of the numerical value, such as less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1% or less than or equal to ± 0.05%. For example, "substantially" aligned can refer to a range of angular variation of less than or equal to ± 10 °, such as less than or equal to ± 5 °, less than or equal to ± 4 °, less than or equal to ± 3 °, less than or equal to ± 2 °, less than or equal to ± 1 °, less than or equal to ± 0.5 °, less than or equal to ± 0.1 °, or less than or equal to ± 0.05 °.

Additionally, quantities, ratios, and other numerical values may sometimes be presented herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and should be interpreted flexibly to include numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, etc.

Although the description herein contains many specifics, these should not be construed as limiting the scope of the disclosure, but merely as providing illustrations of some of the presently preferred embodiments. Accordingly, it will be appreciated that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art.

All structural and functional equivalents to the elements of the disclosed embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein should be construed as a "means plus function" element unless such element is explicitly recited using the phrase "means for … …". No claim element herein should be construed as a "step plus function" element unless such element is explicitly recited using the phrase "step for … …".

Table 1

Discovery zone formation illustrated in fig. 33

Claims (20)

1. An apparatus for wireless communication in a mesh network, the apparatus comprising:

(a) wireless communication circuitry configured to wirelessly communicate with other wireless communication stations using directional transmission having a plurality of antenna pattern sectors, wherein each antenna pattern sector has a different transmission direction;

(b) a processor coupled to the wireless communication circuitry; and

(c) a non-transitory memory storing processor-executable instructions;

(d) wherein the instructions, when executed by a processor, perform steps comprising:

(i) transmitting a peer beacon, which is a first type of beacon, including time synchronization and resource management information to maintain existing links between one or more neighboring peers within the mesh network; and

(ii) transmitting a network discovery beacon, which is a second type of beacon, containing mesh profile information identifying the mesh network to assist in network discovery for wireless communication stations to join the mesh network.

2. The apparatus of claim 1, wherein the directional transmission assists scanning for mesh network discovery and maintaining links between peers in the mesh network.

3. The apparatus of claim 1, wherein the instructions, when executed by a processor, perform transmission of the first type of beacon from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on peer location.

4. The apparatus of claim 1, wherein the instructions, when executed by a processor, perform transmission of the second type of beacon with coordination between stations in the mesh network, whereby not all stations need to transmit the second type of beacon.

5. The apparatus of claim 1, wherein the instructions, when executed by a processor, further perform the steps of: searching for available networks in the vicinity using active scanning or passive scanning, and responding to receipt of the network discovery beacon by transmitting a signal to notify an intention to join the mesh network.

6. The apparatus of claim 1, wherein the instructions, when executed by a processor, further perform the steps of: transmitting a signal notifying of an intent to join the mesh network, wherein at least one station in the mesh network receiving the signal notifying of the intent to join the mesh network schedules transmission of a discovery beacon to stations searching to join the mesh network.

7. The apparatus of claim 6, wherein the instructions, when executed by a processor, further perform the steps of: transmitting to a scheduling entity of the mesh network a subset of information received from stations that sent the signal notifying of the intent to join the mesh network, wherein the scheduling entity of the mesh network collects information from stations in the network, determines a transmission time and at least one transmitting station to generate the discovery beacon, and transmits to the stations a notification regarding the transmission time of the discovery beacon.

8. The apparatus of claim 7, wherein the instructions, when executed by a processor, further perform the steps of: transmitting a discovery beacon in response to receiving an instruction from the scheduling entity of the mesh network to transmit a discovery beacon at the transmission time.

9. The apparatus of claim 1, wherein the instructions, when executed by a processor, further perform the steps of: the method includes collecting information about a station newly joining the mesh network from its neighboring peer stations, determining a transmission timing of a discovery beacon, and transmitting the discovery beacon at the determined timing.

10. The apparatus of claim 1, wherein the instructions, when executed by a processor, further perform the steps of: coordinating transmission of network advertisement frames between stations in the mesh network, wherein, in response to the coordination, at least one of the stations in the mesh network transmits the network advertisement frames to a new node in all directions during a data transmission period to assist in neighbor discovery.

11. An apparatus for wireless communication in a mesh network, the apparatus comprising:

(a) wireless communication circuitry configured to wirelessly communicate with other wireless communication stations using directional transmission having a plurality of antenna pattern sectors, wherein each antenna pattern sector has a different transmission direction;

(b) wherein the directional transmissions facilitate scanning for mesh network discovery and maintaining links between peer stations in the mesh network;

(c) a processor coupled to the wireless communication circuitry; and

(d) a non-transitory memory storing processor-executable instructions;

(e) wherein the instructions, when executed by a processor, perform steps comprising:

(i) transmitting a peer beacon, which is a first type of beacon, including time synchronization and resource management information to maintain existing links between one or more neighboring peers within the mesh network; wherein the first type of beacon is transmitted from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on a peer location; and

(ii) transmitting a network discovery beacon, which is a second type of beacon, containing mesh profile information identifying the mesh network to assist network discovery to join wireless communication stations in the mesh network, wherein the second type of beacon is transmitted after coordination among stations in the mesh network such that not all stations need to transmit the second type of beacon.

12. The apparatus of claim 11, wherein the instructions, when executed by a processor, further perform the steps of: searching for available networks in the vicinity using active scanning or passive scanning, and responding to receipt of the network discovery beacon by transmitting a signal to notify an intention to join the mesh network.

13. The apparatus of claim 11, wherein the instructions when executed by a processor further perform the steps of: transmitting a signal notifying of an intent to join a mesh network, wherein at least one station in the mesh network receiving the signal notifying of the intent to join the mesh network schedules transmission of a discovery beacon to stations searching for to join the mesh network.

14. The apparatus of claim 13, wherein the instructions when executed by a processor further perform the steps of: transmitting to a scheduling entity of the mesh network a subset of information received from stations that sent the signal notifying of the intent to join the mesh network, wherein the scheduling entity of the mesh network collects information from stations in the network, determines a transmission time and at least one transmitting station to generate the discovery beacon, and transmits to the stations a notification regarding the transmission time of the discovery beacon.

15. The apparatus of claim 14, wherein the instructions, when executed by a processor, further perform the steps of: transmitting a discovery beacon in response to receiving an instruction from the scheduling entity of the mesh network to transmit a discovery beacon at the transmission time.

16. The apparatus of claim 11, wherein the instructions when executed by a processor further perform the steps of: the method includes collecting information about a station newly joining the mesh network from its neighboring peer stations, determining a transmission timing of a discovery beacon, and transmitting the discovery beacon at the determined timing.

17. The apparatus of claim 11, wherein the instructions when executed by a processor further perform the steps of: coordinating transmission of network advertisement frames between stations in the mesh network, wherein, in response to the coordination, at least one of the stations in the mesh network transmits the network advertisement frames to a new node in all directions during a data transmission period to assist in neighbor discovery.

18. A method of wireless communication in a mesh network, the method comprising:

(a) transmitting a peer-to-peer beacon, which is a first type of beacon, including time synchronization and resource management information to maintain existing links between one or more neighboring peer stations within a mesh network of wireless communication stations utilizing directional transmission having a plurality of antenna pattern sectors, each antenna pattern sector having a different direction of transmission; and

(b) transmitting a network discovery beacon, which is a second type of beacon, containing mesh profile information identifying the mesh network to assist in network discovery to join a wireless communication station to the mesh network.

19. The method of claim 18, further comprising transmitting the peer beacon from the plurality of antenna pattern sectors to a reduced number of antenna sector directions based on a peer location.

20. The method of claim 18, further comprising utilizing coordination between stations in the mesh network to transmit the discovery beacon, whereby not all stations need to transmit the discovery beacon.

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